Supporting Documents Self Employed

[pammy124]

Hi all,
We are currently exempt from the financial requirement as I receive disability living allowance. I have been self employed since last year but make about £5000 a year, earnings which are irregular ie one week I can make alot and go without any work for weeks.
We want to put in an application for my proposed partner for partner visa with intention to marry within 6 months but we are not sure what evidence to put in with regards to me been self employed. We currently meet the adequate maintenance after rent is paid.

My question is:
Do I need to provide at least 12 months tax returns as well as 12 months bank statement or will the normal 3-6 months bank statements plus a tax return from HMRC be enough?
I get paid cash in hand,even though I do use some of the money before I put it in the bank, I do declare all my earnings so they may be a slightly less funds showing in my account compared to what is on my tax returns forms. Will this be a problem?

Please help! I am really confused about the self employed aspect and evidence.